JPH0318943B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is based on the shaft sealing of a needle valve that opens and closes a paint discharge port using a sleeve made of synthetic resin. This invention relates to a spray gun that can be maintained smoothly.

[Conventional technology]

Conventionally, the needle valve for opening and closing the paint discharge port at the tip of the paint flow path provided in a spray gun is located at the rear end of the paint flow path B, where the needle valve A protrudes from the head of the gun, as shown in Figures 3 and 4. At the part passing through the guide hole C, a tightening screw D screwed in from the rear end of the guide hole C presses the rear surface of the seal ring E such as a gasket or an O-ring, thereby pinching the seal ring E. Needle valve A
The shaft is sealed.

In addition, a small-diameter insertion port H is provided in the front part of the guide hole C, through which the needle valve A is inserted through a small gap G through a wall that supports the front surface of the seal ring E.

[Problem that the invention seeks to solve]

However, with such a shaft-sealing structure of the needle valve A, paint tends to enter the small gap G, and when the spray gun is incompletely cleaned, the hardening of the paint may cause the needle valve to malfunction. . In particular, the insertion hole H
Since the spray gun is provided on the spray gun body made of a light alloy such as aluminum, the metal surface is exposed and the intruding paint or hardened paint will firmly adhere to the spray gun body.

Furthermore, in recent years, adhesives, especially two-component adhesives, have been applied using spray guns. Defects tend to occur.

Note that the insertion hole H is a part of the hole extending over the entire length of the spray gun body through which the needle valve A is inserted, and the portion other than the insertion hole H is formed with a large diameter, so that the insertion hole H is not inserted through the hole H. As a result of machining difficulties in reducing only the diameter of the hole H, the small gap G is formed between the insertion hole H and the needle valve A, into which paint can enter.

The present invention is based on the principle of eliminating the exposure of the metal surface by providing a sleeve made of synthetic resin in addition to the seal ring, thereby preventing the adhesion and hardening of the paint, and solving the above-mentioned problems. The purpose is to provide

[Means for solving problems]

Hereinafter, one embodiment of the means of the present invention capable of achieving the above-mentioned objects and solving the problems will be described based on the drawings.

In the figure, the spray gun 1 has a needle valve 5 for opening and closing the paint discharge port 4 at the tip of the paint flow path 3 of the spray gun body 2, and a guide hole 6 at the rear end of the paint flow path 3.
The shaft is sealed using a synthetic resin sleeve 7 and a seal ring 9.

In this embodiment, the spray gun body 2 has a trigger 2.
The trigger 21 is pivotally supported by the body 22 and has a head 23 at the front end of the body 22 and a handle 24 at the rear end.
3. Suspended within the space 25 between the handles 24, and the trigger 2
1, the needle valve 5 extending from the handle 24 through the cavity 25 to the head 23 and the air opening/closing valve 20 protruding from the handle 24 can be actuated.

The needle valve 5 consists of a front stem 29 whose rear end is screwed together with a cylindrical plunger 27, and a rear stem 30 whose front end is screwed together with the plunger 27, and each thread diameter of the front stem 29 and rear stem 30 is By differentiating the numbers, errors in attachment to the plunger 27 are eliminated. Further, the needle valve 5 is supported via the plunger 27 by a support fitting 32 screwed into a hole 31 provided in the handle 24. Further, the needle valve 5 is biased forward by a spring 35 disposed between the rear end of the plunger 27 and an adjusting screw 34 screwed into the rear end of the hole 31, and as the adjusting screw 34 is screwed forward and backward, the needle valve 5 is The amount of retraction can be adjusted.

The needle valve 5 passes through the paint flow path 3 and opens and closes the paint discharge port 4 at its front end by moving forward and backward.

The paint flow path 3 consists of a center hole 40 of a paint nozzle 39 screwed together at the tip of the head 23, and an inner hole 41 formed in the head 23 through which the center hole 40 communicates. is provided with a side hole 42 communicating with a nipple 43. Further, the guide hole 6 for guiding the needle valve 5 into the cavity 25 is formed at the rear end of the paint flow path 3. The guide hole 6 has a front hole 46 which is connected to the inner hole 41 and has a slightly smaller diameter than the inner hole 41, and a middle hole 47 and a screw hole 49 are connected to the front hole 46, and the screw hole 49 is connected to the head 23.
Opens at the back.

A sleeve 7 and a seal ring 9 are arranged in parallel in the guide hole 6.

The sleeve 7 is formed using a synthetic resin such as fluororesin, ie, Teflon (trade name), which has a low coefficient of friction, wear resistance, corrosion resistance, self-lubricating property, non-adhesion of paint, etc. . As shown in an enlarged view in FIG. 2, the sleeve 7 has a stepped cylindrical shape with a small diameter part 51 that fits into the front hole 46 and a large diameter part 52 that fits into the middle hole 47. A support hole 53 is provided between the needle valve 5 and the needle valve 5 so that the needle valve 5 can be slidably held therein with an extremely small gap or almost in contact with the needle valve 5. The front surface of the sleeve 7 is exposed to the paint flow path 3, and the rear surface has a
For example, a seal ring 9 using an O-ring made of a similar synthetic resin is arranged in parallel.

As the seal ring 9, in addition to an O-ring, a so-called seal made of rubber, leather, etc. can also be used.

Further, the seal ring 9 is pressed by the cone surface of the front end of the screw 54 which is screwed into the screw hole 49, and the seal ring 9 comes into contact with the hollow hole 47 and the needle valve 5.

Therefore, the needle valve 5 is axially sealed by the sleeve 7 and the seal ring 9 between the guide hole 6 which is connected to the paint flow path 3.

Note that the needle valve 5 is moved backward by pressing the front end of the plunger 27 by the trigger 21.
The paint discharge port 4 having a tapered valve seat at the tip of the paint nozzle 39 can be opened and closed, and by releasing the trigger 21, the paint discharge port 4 is moved forward by the spring 35.
Close.

Further, a paint supply device 10 such as a paint cup or a paint pump is attached to the nipple 43, and the paint supply device 10 is communicated with the paint flow path 3.

An air hole 57 leading from the nipple 56 at the lower end of the handle 24 communicates with an air hole 60 provided in the body 22 via a control valve 58 for adjusting the amount of air, the air opening/closing valve 20, and an oblique hole 59.

Moreover, the air hole 60 has a circumferential groove 61 and a paint nozzle 39.
It communicates with the air outlet 11 at the tip of the air cap 64 through a small hole 62 in the periphery. Also, a circumferential groove 65 and a notch 66 provided in the flange around the paint nozzle 39.
The air cap 64 is connected to a pattern hole 67 of the air cap 64. An adjustment screw 69 for adjusting the pattern, which has a valve shaft approaching the tapered portion at the tip of the air hole 60 and adjusts the amount of air flowing into the pattern hole 67, is provided at the rear of the upper end of the handle 24.

[Effect]

Therefore, by operating the trigger 21, the air opening/closing valve 20 is opened and the plunger 27 of the needle valve 5 is moved backward, so that the needle valve 5 opens the paint discharge port 4. Therefore, the air from the air outlet 11 atomizes the paint flowing into the paint flow path 3 from the paint supply tool 10 and allows it to be atomized and jetted from the paint outlet 4.

The needle valve 5 is supported by a sleeve 7 made of synthetic resin, and the sleeve 7 is exposed to the paint flow path 3, while the sleeve 7 and the needle valve 5 are slidably in contact with each other or have a very small diameter. As a result of having a gap, it is possible to prevent paint from flowing into the gap. Further, since the sleeve 7 is made of synthetic resin, the support hole 53 has a synthetic resin surface, so even if paint enters the support hole 53, it is prevented from adhering to the inner surface of the support hole 53, and its removal is easy. It becomes extremely easy.

Furthermore, by attaching the sleeve 7, the diameter of the guide hole 6 is increased, its workability is improved, and the inner diameter of the guide hole 6 or the concentricity with the hole portion 31 and the inner hole 41 is improved. Therefore, the sleeve 7 can be mounted with high precision, and together with the seal ring 9, the shaft sealing effect of the needle valve 5 can be improved.

〔Effect of the invention〕

As described above, in the spray gun of the present invention, the needle valve that opens and closes the paint discharge port of the paint flow path of the spray gun body and the guide hole that is connected to the paint flow path can be loosely inserted relatively densely. Since the shaft is sealed using a synthetic resin sleeve and a seal ring, the insertion hole that passes through the needle valve A with a small gap G, as in the conventional spray gun shown in Figs. There is no exposed metal surface on the inner surface, which prevents malfunction of the needle valve due to paint adhesion. In addition, the diameter of the guide hole can be increased by using the sleeve, which improves the machinability of the guide hole itself and improves the precision of the guide hole, making it possible to hold the needle valve correctly and improving operability. This effect can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
The figure is an enlarged sectional view of the guide hole, FIG. 3 is a sectional view of the head of a conventional spray gun, and FIG. 4 is an enlarged sectional view of the guide hole. 2... Spray gun body, 3... Paint flow path, 4
...Paint discharge port, 5...Needle valve, 6...Guiding hole, 7...
...Sleeve, 9...Seal ring, 10...Paint supply tool.

Claims (1)

[Claims] 1. A needle valve that passes through the paint flow path of the spray gun body leading to the paint supply tool and opens and closes the paint discharge port at the tip of the paint flow path, and a guide hole that the needle valve passes through and is connected to the paint flow path. , a sleeve made of synthetic resin that fits into the guide hole and allows the needle valve to be loosely inserted relatively tightly;
A spray gun whose shaft is sealed using a seal ring arranged in parallel with the sleeve and fitted into the guide hole.